Select the 'Accept' or 'Prompt' option under 'Third-party Cookies.' (Note: if you select the 'Prompt' option, you'll be prompted to click OK every time a website attempts to send you a cookie.)

In the Internet Options window, click OK to exit.

Mozilla Firefox

To enable cookies in Mozilla Firefox 3.x (PC):

Click Tools > Options.

Click Privacy in the top panel.

Set 'Firefox will': to Use custom settings for history.

Check the box next to Accept cookies from sites to enable cookies, or uncheck it to disable them.

Click OK.

To enable cookies in Mozilla Firefox 2.x (PC):

Click Tools > Options.

Click Privacy in the top panel.

Select the checkbox labeled 'Accept cookies from sites.'

Click OK.

To enable cookies in Mozilla Firefox (Mac):

Go to the Firefox drop-down menu.

Select Preferences.

Click Privacy.

Set 'Firefox will': to Use custom settings for history.

Check the box next to Accept cookies from sites to enable cookies, or uncheck it to disable them.

Click OK.

Chrome

To enable cookies in Chrome (PC):

Click the Tools menu.

Select Options.

Click the Under the Hood tab.

Click Content settings in the 'Privacy' section.

Make sure Allow local data to be set is selected to allow both first-party and third-party cookies. For any given webpage, first-party cookies are cookies that are set by the site domain listed in the address bar. Third-party cookies come from other domain sources that have items, such as ads or images, embedded on the page. If you only want to accept first-party cookies, check the box next to Block all third-party cookies without exception.

To enable cookies in Chrome (Mac):

Select Chrome > Preferences on the menu bar.

Click the Under the Hood tab.

Click Content settings in the 'Privacy' section.

Make sure Allow local data to be set is selected to allow both first-party and third-party cookies. For any given webpage, first-party cookies are cookies that are set by the site domain listed in the address bar. Third-party cookies come from other domain sources that have items, such as ads or images, embedded on the page. If you only want to accept first-party cookies, check the box next to Block all third-party cookies without exception.

Safari

To enable cookies in Safari:

Go to the Safari drop-down menu.

Select Preferences.

Click Security in the top panel.

Under 'Accept Cookies' select the option 'Only from sites you navigate to.'

*** If you've already checked that your cookies are enabled and you're still seeing an error message that your browser's cookie functionality is turned off,
try opening a new window in your browser. Sometimes using tabs in a single browser instance can cause your cookies to stick.